Where does this strange and popular letter come from? Well, surprisingly the story begun in Córdoba, or should I say the Córdoba Caliphate. The term “arroba” comes from the Arab  الربع (ar-rubʿ) which means the quarter of something (¼) and was widely used in Spain around the IXth century, one unit was equivalent to 25 pounds, in other words one unit was equivalent to one quarter of a quintal or centner: 11,5 kilograms.

This unit of mass was very common during the centuries of Muslim presence in Spain but then it continued to be used even in the Spanish America and the rest of the Spanish Empire. Hence it became an international unit of mass. All the ships going to America or coming from America measured its mass cargo using this particular unit of mass, even for the British America.

Given the intense use of this term for the unit of mass a sign was needed, easy to reproduce an very easy to recognize in any document, just like the dollar sign ($). The chosen symbol came from the Latin and constitutes a reference to the ad- preposition, which means “until” or “towards”. Monks during the Middle Ages used that so often that they ended up joining both letters. In Spanish and Portuguese the @ symbol was used to signify the Arab unit of mass ar-roub.

The first written case of this symbol was discovered the year 2000, it is a document signed by Francesco Lapiun, an Italian merchant who sent it from Seville to Rome in the year 1536. It is an important document that describes the cargo brought from America by three ships.

During the XIXth century this unit of mass was one of the most used in Europe and America; even the newly developed typewriters had a key for it; an from that day onwards it never abandoned our keyboards. Then came Christopher Scholes, who in 1868 developed a system to unify all existent keyboards for typewriters. He would sell the patent to Remington in 1873. The QWERTY keyboard received its name from the first six letters in its upper row.

And then the @ sign lingered, a strange key getting stranger for most new users, and it was close to disappearing but then in 1971 Ray Tomlinson, a US programmer, developed the first electronic mail system ever and chose that symbol to separate the name of the person from the place where that person was.

The idea behind his decision was to use a letter from the typewriter keyboard that would not appear in names nor in servers. At the time, the @ was a key within the keyboard but had no use whatsoever, hence, it did not interfere with names of any sort. Tomlinson sent himself the first e-mail ever, he did so using his computer and sending it to another machine right next to his.

The rest is history. Today the @ sign is as popular key as they come, more even than most letters of the alphabet. For us, citizens of Córdoba, it means something to have remotely contributed in unimaginable ways to the great technological revolution of our time.

(He who does not find comfort for himself does so willingly for there are plenty of other options.)